texts: If you lived on the far side of the Moon, how could you infer the existence of Earth?

texts:
Suppose that you deposit an astronomer, armed with our current knowledge of orbital mechanics, on a dome on the far side of the Moon, so that the Earth is perpetually hidden from them.

(And, of course, assume that this person has no specific knowledge about the system they're in beyond what they can glean from observations. If you will, imagine that they learned all our modern orbital mechanics and related physics in alpha centauri, and then got teleported to our Moon.)

Now, it is reasonable to expect that this person should be able to deduce from observations of the sky that the body they are on is one half of a binary system, and they should be able to measure the orbital characteristics (semi-major axis, ellipticity, inclination) as well as the  position of the barycentre (much closer to the other body, corresponding to a much more massive partner). What observations are needed to deduce this? What level of observational accuracy is needed for those observations, and to what historical epoch does it correspond to? (I.e. would Tycho Brahe's kit have been sufficient? Would Galileo's? Would the ancient Greeks'? Or would this require a late-19th-century (or even later) observatory?)

(As pointed out in MartinV's answer, our astronomer might find it hard to distinguish between situations with an orbiting pair vs one single huge body. Thus, if convenient, you can assume that, via short ~100km forays from the dome, our astronomer is able to measure the lunar radius by measuring solar inclinations at different points with known distances between them, à la Erathostenes.)


texts: Is it possible to generate random numbers from images of the sun?

texts:
If this is off topic, please change it to world-building.

Is it possible to make a low cost heliography telescope, which is not digital, and which can be used to generate an worldwide numerical fingerprint using sun spot positions as a mathematical code?

Every city in the world would have the same heliograph. Nearly all the sunlit heliographs of the world would agree what the sunspot fingerprint code is. The sun generated code would then decide who's turn it is to record financial verification tasks, government accounts, and other corruption issues.

Would other cosmic signals be more practical to graph and suited to that end?

Does the sun change too slowly to be useful for generate a daily random code? what about weekly?

Do you have any tips of how to design a simple analogue heliograph that converts sunspots into random numerical code, (i.e. to make a crypto currency called Sun-Peso/ to decide an olympic host country)?


texts: How large could a second moon of Earth be?

texts:
Question in the title. Let's say that I have a lot of garbage- mined-out asteroids, spent nuclear fuel, satellite debris, and just general trash. Also safe ways to get these into Earth orbit. Instead of sending this into the Sun, Jupiter, or out of the Solar System's plane, what if I took some random quasi-satellite, put it a bit behind the Moon on its orbital path, and started piling garbage on it?

How large could it get before bad things start happen to Earth? For example, tides drowning the coasts. I'm not going to consider collisions, because of (insert megacorp here) Moon Tethers™.


texts: Were K2-141b and WASP-63b selected as the first two exoplanet atmospheres for JWST to look at during its first year of observations? If so, why?

texts:
In The Observatory @Donald.McLean linked to Scientists will peer at first galaxies with James Webb telescope which says in part:

The new telescope will augment science performed by Hubble, not necessarily replace it, (Nestor) Espinoza said. He is part of the James Webb team at the organization that manages science done with such space instruments, a Baltimore-based a non-profit consortium of scientists that advises NASA.
Espinoza will serve as the principal scientist on projects in which the Webb telescope will examine two planets in distant planetary systems. One of them, K2-141b, is about 50 percent larger than Earth, while the other, WASP-63b, is a gas giant similar to Jupiter.
"Hubble can't perform the kinds of observations we need to learn about the atmospheres of these planets, or other details, since it was designed before the first planets outside our solar system were detected," Espinoza said.

Also

Many of the proposed tasks for the Webb telescope were planned and approved in the 1990s as the observatory was under initial development, said Klaus Pontoppidan, an astronomer and Webb project scientist at the institute.
"We've just added the final projects that will be included during the first year or 13 months," Pontoppidan said.

I don't know if K2-141b and WASP-63b are the first exoplanets that JWST will look at in the first round of observations, or just two examples of many. I also don't know if these exoplanets had even been discovered yet when "(m)any of the proposed tasks for the Webb telescope were planned and approved in the 1990s..."
So I'd like to ask:
Question: Were K2-141b (50 percent larger than Earth) and WASP-63b (gas giant similar to Jupiter) selected as the first two exoplanet atmospheres for JWST to look at during its first year of observations? If so, why? If not, how many other exoplanet atmospheres are planned to be studied during this period?


texts: Do main sequence stars in binaries transfer mass by Roche lobe overflow?

texts: It is known that binary star components containing red giant can under go mass transfer when their radii exceeds the Roche limt. Do main sequence binary stars also undergo mass transfer by this mechanism?


texts: What leads an observer to choose a narrow slit over a wide one (and vice-versa) when observing?

texts: In spectroscopy, a wide slit will lead to lower spectral resolution while too narrow of a slit will reduce incoming flux from the object. From what I read, it appears as though there is always a balance between spectral resolution and throughput. I'm looking for examples when an observer may choose one "extreme" over the other. ie. a very narrow slit or a wide slit (let's leave slitless spectra out of the convo for now unless relevant). What types of scenarios would motivate an observer towards one of the tradeoffs?


texts: From whence is the Event Horizon Telescope black hole data available for amateur reconstruction?

texts:
Ralf Vandebergh's tweet shows his own reconstruction of an image of the accretion disk around a black hole, generated presumably from Event Horizon Telescope data.

I'm assuming that the data came from a publicly available source, but I don't know for sure. That would make sense, they used two completely independent groups to reconstruct the images to cross-check each other before they were published, because with so few of the telescopes in the array recording data at any one time, the reconstruction took a bit of artistic license or "filling in".

Since the raw data is huge, boxes and boxes of hard drives with high speed digital recording of GHz rate ADC conversions, I don't think there's an ftp site for the actual raw data. And since calibrations and baselining is pretty complicated, it would be hard to reconstruct.

So I'm wondering what kind of data is available that would allow someone to reconstruct their own EHT image?

FYI Ralf Vandebergh's astrophotography can be found in links within Why exactly do “CMOS astrophotographers” prefer CMOS sensors?

From tweet:

  This is one of my processings of the #blackhole #EHTBlackHole first ever image. @RHdijkgraaf @govertschilling @NASAblueshift @ehtelescope @jordydavelaar @UofA @perimeter @smithsonian @TheNRAO @PhysicsWorld

 click for larger


texts: What to do in case of concentric circles that are not aligned with the cross after collimation (Picture inside)?

texts:
I have been collimating my newly bought first Newtonian telescope for a few days now, but I can't get the center of the circles to align with the intersection point of the spider's reflection. I have drawn a simple picture that illustrates what I see:

My question is, which mirror do I need to adjust, and in which way, in order to get the cross to align with the circles in the correct way.
Thanks in advance.
Edit:
If this is something that is not supposed to happen, then please tell me so that I would contact the seller. Thanks again.


texts:
Which is more rare: Lunar eclipse or Solar eclipse? Please explain why either one is more rare than the other.

Thank you in advance for your inputs.


texts: Almost all gas giants in our solar system are observed to have a planetary ring comprises of ice, dust and rocks. My question is do these rings obediently sticks around their foster parent until our starving Sun becomes red giant? Also why don't the ring forms into moon?


texts: What effects do other planets have on the solar system?

texts:
For instance, Jupiter is the biggest planet in our solar system. Due to it's gravitational mass it can deflect meteorites and protect Earth from the Oort cloud.  While these are positives, the negative effects are that Jupiter can draw comets in from the Kuiper belt which may have catastrophic consequences.

Do other planets have a similar effect on the solar system?


texts: What's the difference between Supergalactic and Equatorial coordinates?


texts:
This answer to Where have all the Vulcanoids gone? links to the aptly-titled The YORP Effect Can Efficiently Destroy 100 Kilometer Planetesimals At The Inner Edge Of The Solar System which says in part:

... The YORP effect destroys Vulcanoids by spinning them up so fast that the gravitational accelerations holding components of the body together are matched by centrifugal accelerations, this causes the body to rotationally fission. i.e break apart. We calculated the timescale of this fission process for a parent Vulcanoid and for each of their subsequent generational fragments. We show that objects with radii up to 100 kilometers in size are efficiently destroyed by the YORP effect doing so in a timescale that is much younger than the age of the Solar System...

Tha answer also links to the explanation of the YROP effect in The YORP Effect and Bennu
 which says:

The YORP effect is a similar phenomenon that affects the rotation rate and pole orientation of an asteroid. YORP is an acronym that combines four scientist’s names: Yarkovsky, O’Keefe, Radzievskii, and Paddack. Building on the work of Yarkovsky, V. V. Radzievskii showed in 1954 that variations in albedo across the surface of a small body in space could increase its rotation rate. This phenomenon is essentially the Crooke’s radiometer effect. Stephen Paddack and John O’Keefe, who were separately working on the origin of tektites and interplanetary dust, went on to show that an object’s shape strongly influences the change in rotation. David Rubincam synthesized these ideas in 1999, and showed that YORP creates a thermal torque akin to a “windmill” effect on asteroids. This torque can modify the rotation rate and obliquity of an asteroid, depending on the external geometry of the body.

This is frustrating because of course the Crooke's radiometer works by interacting with the molecules of the low pressure gas intentionally included inside the glass bulb, and not by radiation, but at least we get the idea that a net torque is produced due to a non-uniformity of some optical property.
Wikipedia's Yarkovsky–O'Keefe–Radzievskii–Paddack effect works hard to try to explain but the explanation is long and I am not confident it's actually accurate.
Answers to What is the difference between the Yarkovsky effect and YORP effect? touch on this but do not answer this question.
Question: What is the YORP effect exactly? Is it just the non-central component of the Yarkovsky effect?

Yarkovsky only considers the center of mass recoil from thermal radiation of a rotating body in sunlight, is YORP just the tangential component of this recoil?
Or does it require the body to be non-uniform in order to spin-up the body?
Would a uniform sphere in fact spin-down?


texts: What is the naming convention for newly discovered objects?

texts:
Often, a newly discovered star is identified by a seemingly random string of letters and numbers. I'm sure that there is some order to it, though. What is the naming convention for newly discovered astronomical objects?

I'm sure NASA doesn't ask the public, as something like this would happen:


texts: What will be the impacts on the planets' orbits from Gliese 710?

texts:
In 1.5 million years, the star Gliese 710 is expected to pass through the Oort cloud. Now obviously this will shower the inner solar system with comets, but the Wikipedia page doesn't say anything about the star's impact on the orbits of the planets.

Will the star not throw the Earth and other planets into highly elliptical orbits, destroying all life? Or, simply, do we not know because this would involve solving the 11-body problem?


texts: Current delay for radio signals from the Mars InSight mission

texts:
I've been meaning to post it on the day when InSight landed but just got around to it now.

When they broadcasted landing in real-time, it really wasn't in real-time because radio signals from Mars can take from 3 to 24 minutes to reach the Earth (depending on the distance between Mars and Earth) if I am not mistaken.

So what was the delay on the date InSight landed? Each time someone mentioned "real-time" I cringed a little bit because everything already happened some time ago and we were just only learning about it now.


texts: What is meant by the bifurcation of hydrostatic equilibrium shapes in planetary formation?

texts:
An intriguing comment below this question links to this Quora question and points to the answer by Robert Walker.

The sentence that particularly intrigued me is:

  It turns out that there are two possible solutions, as the spin rate increases. You can get an oblate spheroid, or a triaxial ellipsoid - the solution "bifurcates". But the triaxial ellipsoid is the most stable of the two as Jacobi found out in his paper published in 1834.  Figures of Equilibrium - Historical Account* - Chandrasekar

It seems to refer both to an 1834 paper by Jacobi and it's reference in the 1964 paper Ellipsoidal figures of equilibrium—an historical account by S. Chandrasekhar, Communications on Pure and Applied Mathematics, 20 (2), May 1967, 251–265. While the latter is paywalled, there seems to be a readable version here in google in the book A Quest for Perspectives: Selected Works of S. Chandrasekhar : with Commentary By Subrahmanyan Chandrasekhar, Kameshwar C. Wali, Volume 1. Imperial College Press, 2001.

Mathematical bifurcation is a fascinating topic and there is even an entire mathematics journal dedicated to the subject.

In this case, where exactly in the calculation of hydrostatic equillibrium of rotating bodies does this bifurcation (mentioned in the Quora answer) occur? I'm wondering if it simply means that for a given volume and density, below a certain rotation rate the hydrostatic equilibrium shape is an oblate sphere, but above it, the hydrostatic equilibrium shape will be a triaxial ellipsoid? Or is the bifurcation part of the evolution of the shape over time, involving viscocity or external effects?

If the triaxial ellipsoide is always(?) the most stable, then is a oblate spheroid actually an intermediate shape, and not really the shape of hydrostatic equillibrium?


texts: Is there a way to know how the magnetic field was at the very beginning of our universe?

texts:
I recently read that

  Gamma-ray bursts are catastrophic events, related to the explosion of massive stars 50 times the size of our sun. If you ranked all the explosions in the universe based on their power, gamma-ray bursts would be right behind the Big Bang,

I'm asking this question in the tentative to compare the Big Bang to a gamma-ray burst. I keep in mind that a key difference between both is that Big Bang was Not an explosion, but want to know similarities to point out.

Near the formation of a black-hole they tell in this same article that matter and magnetic field play a key role the gamma-ray bursts.

I know magnetic fields are induced by charge displacement. Is it possible there was a kind magnetic field before protons and electrons formed, or during the first expansion phase?

Here are pictures I modified from Wikipedia's chronology of the universe to illustrate:

Do we have a way to know how magnetic fields were at that time?

Close-up (image borrowed from donsnotes ):

Any way we could have information on magnetism at this point of universe creation?

In the Electroweak Era?
During the Great Unification Theory (GUT) Era?
And then in the Plank Era?


texts:
To my (admittedly limited) understanding a human being in outer space wouldn't last very long, mainly due to three factors:

the extreme cold
the intense radiation
and the vacuum of space

So if my understanding is correct, humans would die within seconds (if anyone could put an approximate number on this that would be great!).

What I want to know is that if a human being was exposed to space for half that time, would they suffer lasting and life threatening after effects?

In other words, is there any amount of exposure to space that wouldn't result in your imminent or eventual death?

Would exposure of just a hand kill you, or would you just lose that hand?

Would being exposed to space from inside a room with a single open door help much (I am assuming here the room would shield you from much of the radiation in space), or would the other two factors still kill you off?

Please feel free to correct my assumptions wherever I am wrong.

Many thanks for any help offered to my slightly morbid musings on space.


texts: What to observe with a remote telescope close to sunrise time?

texts:
I have an access to a remote telescope at 05.15-05.45 am at Hawaii time. The sun rises at 06.15 am. I will use this telescope for educational purposes for high school students. I wonder 30 mins is enough to make a variable star observation or a spectroscopic measurement.

The specs of the telescope could be found on https://lco.global/observatory/2m/


texts: How much heat emanates from the planets after formation?

texts:
The 2nd answer to this question by MBR got me thinking about this.

Is there some general guideline for residual heat a planet should emit, say 4.5 billion years after formation.   I'm defining heat by the radiant energy that leaves the planet, not internal heat or surface temperature for rocky bodies and assuming little or no solar input.

Wikipedia lists an estimate of planet 9's temperature to be 47 degrees K based on remaining heat of formation, but I think that would depend pretty significantly on it's size as well as whether it had any recent impacts.   I can't help but wonder if that's an accurate estimate.

Jupiter, as one example, emits about twice as much energy as it receives from the sun, and it's temperature is about 128 degrees Kelvin.  Is it safe to assume that Jupiter's upper cloud temperature would still be ~ 100 Kelvin even if it was in deep space, but otherwise having the same formation and history.

Neptune is also a few degrees warmer than Uranus, so has got to be putting out a fair bit of internal heat as well.

Obviously there's a few factors at play - size, whether there was a recent large impact, abundance of radioactive elements, efficiency of circulation (solid layers are likely more efficient at trapping heat than circulating fluid layers).

I'm tempted to guess that there's too many unknowns on gas giant circulation, inner layers, composition and mass for there to be any good simple charts on this stuff, but I was curious if there was anything.   I tried google without success.


texts: Why is the color of the moon so similar to the clouds?

texts: Why the moon looks like the cloud-structure on the blue sky among the clouds?


texts: Does the Sun impose back it's tidal forces onto the Earth (such as the Earth's to the Moon)?

texts:
It is known that each year the Moon is moving away from the Earth due to tidal forces.

What about the Earth relative to the Sun?


texts: What is the mass for a celestial body to definitely achieve hydrostatic equilibrium?

texts:
While these posts (attempt to) answer what the minimum mass is to be able to achieve an ellipsoidal shape, my question asks for the mass at which a body definitely collapses into an ellipsoid. Meaning, from this mass on a body definitely won't be irregular nor borderline but clearly an ellipsoid due to hydrostatic equilibrium. The value will be different for ice dwarfs (like Enceladus and Pluto), terrestrial bodies (like the inner four planets, the Moon and Io) and gas giants. I'm curious on the mass for each of them, I guess in 2021 science has progressed enough to provide an approximate answer.
The largest and most massive object I know of whose sphericity is questionable is Haumea in the Kuiper belt at 0.00066 Earth masses (~ 1/3 Pluto's) and an equatorial diameter at 2322 km (1443 mi).


texts:
I was bopping around YouTube and observed this enjoyably produced video. In it, when describing the behavior of a black hole with the mass of a US nickel, the narrator says, "Its 5 grams of mass will be converted to 450 terajoules of energy, which will lead to an explosion roughly three times bigger than the bombs dropped on Hiroshima and Nagasaki combined."

Of all the fun things illustrated there, that was the one whose pretense I didn't understand. Do black holes explode after they've radiated away all of their mass? Or would the "explosion" just come from the rapid pace at which the black hole would consume nearby matter?

The Googling I've done thus far has provided no firm answer. The closest I've come is from the Wikipedia page on Hawking Radiation, which states, "For a black hole of one solar mass, we get an evaporation time of 2.098 × 10^67 years—much longer than the current age of the universe at 13.799 ± 0.021 x 10^9 years. But for a black hole of 10^11 kg, the evaporation time is 2.667 billion years. This is why some astronomers are searching for signs of exploding primordial black holes."

Some other websites refer to the last "explosion" of the Milky Way's supermassive black hole being some 2 million years ago, but is that the same mechanic mentioned on the Wikipedia page? Or the YouTube video, for that matter?

Thanks in advance. =)


texts: Why don't astronomers use meters to measure astronomical distances?

texts:
In astronomy distances are generally expressed in non-metric units like: light-years, astronomical units (AU), parsecs, etc. Why don't they use meters (or multiples thereof) to measure distances, as these are the SI unit for distance? Since the meter is already used in particle physics to measure the size of atoms, why couldn't it be used in astrophysics to measure the large distances in the Universe?

For example:

The ISS orbits about 400 km above Earth.
The diameter of the Sun is 1.39 Gm (gigameters).
The distance to the Andromeda Galaxy is 23 Zm (zettameters).
At its furthest point, Pluto is 5.83 Tm (terameters) from the Sun.

Edit: some have answered that meters are too small and therefore not intuitive for measuring large distances, however there are plenty of situations where this is not a problem, for example:

Bytes are used for measuring gigantic amounts of data, for example terabytes (1e+12) or petabytes (1e+15)
The energy released by large explosions is usually expressed in megatons, which is based on grams (1e+12)
The SI unit Hertz is often expressed in gigahertz (1e+9) or terahertz (1e+12) for measuring network frequencies or processor clock speeds.

If the main reason for not using meters is historical, is it reasonable to expect that SI-unites will become the standard in astronomy, like most of the world switched from native to SI-units for everyday measurements?


texts: What kind of a visual trajectory would an asteroid have if it were to hit Earth?

texts:
Let's say that Peter has a set of superb telescopes and he's watching the sky every night, for 3-4 months. He may not know it just yet, but there is an asteroid heading towards Earth, on a crash course. He is too lazy to plot an orbit, because he doesn't believe he could die like that.

Over the months the Earth travels quite a lot around the Sun, resulting in various amounts of parallax, depending on the distance. The location of the telescopes are also a factor, and so is the (rotation of the) axis of Earth.

To simplify this and to get rid of Earth radius parallax, Peter is a researcher on the South Pole with those mighty telescopes.
Over the course of months, what kind of a trajectory would a doomsday asteroid make? As it gets bigger/brighter (which is also relative, because the asteroid itself can rotate)/closer, how would its position change, compared to the stars in the background?
Would the change slow down or accelerate? Would it be a small piece of a spiral (I don't mean complete spirals, just the fact that it wouldn't be a parabola or a circle)? What do you think Peter would see if he animated its movement during the course of months on a virtual sky sphere?

The National Geographic article Asteroid Called ‘Spooky’ Will Buzz Earth on Halloween has an animation of the trajectory of asteroid 2015 TB145 (nicknamed Spooky because it looks like a skull).

16 minutes apart visual timelapse:
https://upload.wikimedia.org/wikipedia/commons/e/ec/2015_TB145_discovery.gif


texts:
A lot of you are probably already aware of our meta site, but I wanted to take the time to remind you that it only requires 5 reputation points to participate--and this is a critical part of our site. Meta is where we decide what kinds of questions we like in the community, it is where we pick our topic of the week, it is where we can deal with different issues of site growth. Did you know that we can suggest revisions to the help center? These are the types of things that meta allows us to discuss. In fact, this post would be best suited on meta because it is not about the field of astronomy, but about this site. I have posted it here so that you (especially new users) can see it. Maintaining activity on our meta site is important to the long term health of our site. If we don't have activity there, we could wither and ultimately get shut down. I appreciate the recent surge of questions, but I hope that many of you will stick around and participate in making this site work!

For more on Meta, read this blog post. Though, note that the link to meta is now located under the Stack Exchange dropdown on the black top bar.

Also check out this blog post on the important questions to ask on Meta.

Thanks for your continued contribution to Astronomy Stack Exchange!


texts: Orbital period for a 1 light year object?

texts: How long would the orbital period be for an object the mass of the moon orbiting the sun at 1 light year in a circular orbit?


texts: Does the CMB contain any clues to what caused the Big Bang? Does a mathematical model theorize it?


texts:
I know that light shifts from high frequency(like gama rays) to low frequency (like radio waves) when traveling throw a gravitational field, this is called red shifting.
My question is: Is there a limit to this, what happens to the light wave when it can no longer stretch, does it get destroyed ?

Thanks, and sorry for the dumb question, just curios.

Edit:
From my knowledge and the internet :) Electromagnetic spectrum it states that light is an electromagnetic wavelength and the frequency which the wavelength travels up and down and the distance it's travel it's called spectrum and in that spectrum there is a frequency that is visible to us, but the spectrum is very large, my question is just for curiosity, I want to know if we know what happens when the light gets beyond the spectrum, can it? And I know that the expanding of space-time makes the light stretch from a high frequency spectrum to a low one, but what happens when you go to the limit of the spectrum ? can the wavelength be stretch to the point of "breaking" ?


texts: Is the equinox absolutely true east everywhere?

texts: I've read that only only in the equinoxes do you get to see the sun rise in the exact east regardless where you might happen to be. However I think this is not absolutely true everywhere, but only in the equator, and in the south the Sun will rise just a tiny bit to the north, but this tiny bit to the north is negligible due to how far the Sun is from Earth. If this reasoning is correct, when would the 'true' equinox be for any country in the south? Can you provide an example and how you did it, please?


texts: How many planets have we discovered that can support human life?

texts: I have heard a lot of buzz about distant planets that could potentially be second homes for human existence, but what is that approximate number?


texts: What is the difference between a moon and a random chunk in the rings

texts:
Jupiter has 79 (known) moons, Saturn 82, Uranus 27 and Neptune 14 (numbers come from Wikipedia). These planets also all have rings. The rings are made up of chunks of rock and ice. There also are satellites in between the rings. What distinguishes a moon from any other chunk in orbit around a planet?

If a body is in orbit around a planet, how do you know if it's a moon or if it's part of the ring? Are there orbital characteristics that differ between the two? Is there a lower bound on size or mass for something to be a moon? Is it the density of surrounding bodies? Is there no formal (e.g from the IAU) definition?


texts: Is 486958 Arrokoth (2014 MU69 aka Ultima Thule) the only solar-system object determined to be binary by occultation?

texts:
The asteroid 486958 Arrokoth was discovered to be binary by astronomers lugging a bunch of telescopes around (I think) camping with them. The timing offered additional astrometry for the orbit determination before New Horizon's flyby, and it also served to put an upper limit on any dust or debris cloud around the object that might suggest a farther flyby distance be considered.

Their hard work certainly paid off and an outline of the object was reconstructed, showing that it was likely a binary; two circular objects. This posed a bit of a mystery because there wasn't any periodic variation in brightness detected that would suggest rotation, but that's a different story.

Is this the only solar system object that was discovered to be binary (or higher) via occultation?

above: reconstructed occultation timing from several nearby sites from this answer below: series of images from New Horizons during flyby from this question

1.3 MB GIF: https://i.stack.imgur.com/Ci213.gif also viewable in YouTube


texts: How Long Will Earth's Year be When Our Sun Goes Red?

texts:
We live in a planet that orbits 93 million miles from a G-type main-sequence star, or "yellow dwarf".  That is far enough for a revolution of 365 days.  Such is the case of Kepler's Third Law of Motion--the farther a body is from its parent, the longer it'd take to revolve around it.

But in the far-distant future, our sun will balloon into a red giant, a star big enough to swallow Mercury and Venus out of existence.  Earth and Mars will take their place, and the habitable zone (where liquid water is possible) will be moved from between Mars and Jupiter to between Saturn and Uranus.

So, in the future, Earth will no longer be one AU from the sun, which means a far shorter year.  But has anyone made any calculations as to how much shorter a Terran year will be in this future scenario?


texts: Open source alternative for RegiStar (align, rotate, and combine images into single frame)

texts:
I'm looking for a free, open-source and Linux compatible alternative to the RegiStar software.

I need it to automatically combine several images into a single frame, where each individual image shows a portion of a large observed region.

Individual images also overlap by some amount, and need to be aligned and possibly rotated before superimposing them onto the final frame.

I believe RegiStar does all this but: a- it is not free, b- it is not open-source, and c- it seems to run on Windows only.


texts: Did this paper just argue that there is surely life on Titan?

texts:
I just read the popular press version of a new paper, and now I have a question about Titan.

Here are some quotes from the pop article:

  A rocky, ocean-bearing planet with more than 0.1 percent methane in its atmosphere should be considered a potentially inhabited planet, the researchers say. And if the atmospheric methane reaches levels of 1 percent or more? In that case, “potentially” doesn’t cut it—such a world would “likely” be home to alien life.

...

  Thus, methane and carbon dioxide together, unaccompanied by carbon monoxide, on a rocky, ocean-bearing world would best be interpreted as an airtight sign of anoxic life.

Now, some information about Titan from the Wikipedia page about Titan:

Titan's atmosphere
    Stratosphere:
        98.4% nitrogen
        1.4% methane
        0.2% hydrogen
    Lower troposphere:
        95.0% nitrogen
        4.9% methane
        -OR, depending on who you ask-
        97% nitrogen
        2.7% methane

  The density of Titan is consistent with a body that is about 60% rock and 40% water.

  There are trace amounts of other hydrocarbons, such as [...] carbon monoxide [...].

If I understand correctly, 'trace amounts' of CO is in line with the requirements stated in the Catling paper.

So, is Titan covered in microbes, or what?  Since the article didn't mention Titan, I presume I missed something.  What was it?


texts: How did Copernicus get the idea of heliocentric model?

texts: The heliocentric model marked the beginning of modern astronomy. But what were the reasons which led Copernicus to think that the earth orbited the sun. I've read that his model was based on observations made by some other astronomer. Can anyone describe how he got this idea?


texts: Photometry extinction correction magnitude

texts:
I am learning photometry and I am wondering is the uncorrected extinction instrumental magnitude always less than the corrected extinction instrumental magnitude when applying transformation coefficients?
For example suppose the uncorrected extinction instrumental magnitude is $m^A_V = 10.00,$ will the corrected extinction instrumental magnitude always be greater than $10$?


texts: Is there a reason why the IAU differenciates objects in the SS orbiting the sun into a particular classification but it doesnt for satellites?

texts: The IAU has different classifications for objects in the solar system orbiting the sun, they can be according to their shape and if they clear their neighborhood of other material around its orbits , planets, dwarf planets or Small Solar System bodies. But for objects in the solar system orbiting a planet or a dwarf planet they are all satellites, no matter if they are rounded or if they have an irregular shape like an asteroid. Is there any known reason why this is so? Why is it needed to differenciate its shape when the object it's orbiting the sun, but it isnt needed when the object it's orbiting a planet? (or dwarf planet)?


texts: Can a Ritchey–Chrétien telescope be collimated using a standard Newtonian laser collimator?

texts:
Is it possible to use a standard Newtonian laser collimator, such as this one to collimate an RCT?

If so, is the procedure any different than collimating a Newtonian (i.e. make the laser go into the hole by adjusting the mirrors)?


texts:
Several missions to the Moon have revealed a lunar horizon glow, such as the ones seen below by the spacecraft Surveyor 7 in 1968:

Image source: NASA

According to the NASA article "Model Helps Search for Moon Dust Fountains" written in 2010 suggests the cause of the phenomenon is due to sunlight shining through a dust layer suspended in the very thin atmosphere (exosphere) of the moon.  From the NASA webpage:

  "It has been suggested that electrostatic forces play a role in the ejection of dust from the lunar surface, and its dynamics in the atmosphere, but we really don’t understand how it gets there in such high abundances."

Given that there is no wind or precipitation in the lunar sky, my question is:

What causes the abundance of dust to 'float' in the thin lunar atmosphere?


texts: Why is carbon so rare on the Moon and on Mars?

texts:
Carbon is the fourth most common element in the universe and in the Solar system. It is about the ninth most common element in Earth's crust. It doesn't seem to be part of any of the ten most common compounds in the Earth's crust.

So where is all the carbon hiding?
Why isn't it more common in planetary and lunar crusts?

Is it maybe mostly occurring in volatiles together with hydrogen and oxygen, and has left bodies which lack atmosphere or freezing temperatures? Is it primarily biological processes which binds carbon to solid molecules? Having a look around on Earth's natural surface today, there's lots of solid carbon compounds everywhere, so the contrast is interesting.


texts: How could the loss of the Arecibo Observatory have been prevented?

texts:
Would more preventative maintenance, more regular inspection of the cables have helped?  Robotic/drone inspection systems?  Could the right robotic system have done work to save it in the last few weeks had one been available?
https://www.space.com/arecibo-observatory-radio-telescope-to-be-destroyed


texts: Could iron rain upset tidally locked WASP76b?

texts:
The Jupiter mass planet WASP76b orbits its 1.5*Sunmass star at 0.03AU and is tidally locked. The day side heats to 2400C which vaporizes metals, including iron observed in its atmosphere. The balmy night side is only 1500C causing ferocious winds which carry the iron vapor from hot to cool side. There it condenses, falling as rain.

Could this redistribution of mass change how the planet faces its star, and what could make that happen? For example, if the winds blew only one direction (I don't know why this would occur) might that act as a small spin that tidal locking forces might try to neutralize?


texts: Comparing Light Collection Between Pupil and Telescope?

texts:
The amount of light collected for a period of time is proportional to the area of the collecting aperture. We use our eyes -pupils have diameters of approximately 5 mm-, binoculars and telescopes. How much more light can we collect with a 50mm pair of binoculars compared with our eyes? And with an 8-inch telescope? If we could have access to a 10-meter class professional telescope, how large would the gain be?

50^2/5^2= 100 times more light

8in = 203.2 mm

203.2^2/5^2= 1652 times more light

10000^2/5^2= 4000000 times more light

Did I solve this problem correctly?


texts:
I'd like to be able to find the latitude and longitude on Earth (assuming a sphere is fine) which is closest to Pluto at the current time (or where Pluto is directly overhead).

Is this possible with PyEphem?


texts: Finding the SN explosion time by t-square fitting

texts:
In a couple of papers I've read that it's usual practice to fit early rise of supernova luminosity curve by $t^2$. Let me describe how I see it:

I take the early fast rising part of luminosity curve and then fit them to a curve:

$L = a\cdot\left( t - t_0 \right) ^ 2 + L_0,$

Where $t_0$ is the moment of explosion.

Is this approach right?


texts: How much do starlight and artificial light illuminate the Moon?

texts:
The Moon receives most of its light from the Sun, either directly through sunlight or indirectly through Earthshine. However, there are many other dimmer sources of illumination.

Starlight. This is probably the most important one. Under exceptional conditions, it creates shadows here on Earth.
Artificial light. Mostly city lights and gas flares.
Meteorological activity. Lightning storms on Earth and other planets are visible from space, and here on Earth, they can trigger other sources of light such as firestorms.
Bioluminescence. Light-emitting microorganisms are bright enough and numerous enough to be seen from space.
Transient bright lights. Events such as supernovas and asteroid impacts are rare, but when they happen, they are a significant source of illumination. Over long timescales, for example a billion years, this may be the biggest contributor of non-solar light.

How much do these light sources illuminate the Moon? If there was no Sun, could we still see the Moon with these lights? And of the three Earth-based sources (artificial light, meteorological activity, bioluminescence), which one illuminates the best?


texts: Any examples of a gas object temperature from Doppler broadening along one axis turning out to be wrong because velocity spread was not isotropic?

texts:
Discussions under Mass of the stellar cluster (not the whole galaxy) lead me to mention that when an actual temperature is inferred from a Doppler-broadened line profile (rather than just a linewidth expressed as an effective temperature), we assume that the Maxwell-Boltzoman velocity distribution in the directions perpendicular to the line of sight is the same as that the one measured along the line of sight.
Have there been any examples of this kind of assumption turning out to be invalid later? Some situation where the distribution of velocities turned out to be substantially anisotropic?
I'm not asking for examples of anisotropic velocity distributions, I'm asking for a case where it seemed like a good assumption at the time, but later it turned out something more interesting was going on and the line-of-sight Doppler width did not represent the spread in perpendicular velocities.


texts: Nomenclature of Interstellar Objects and Stars

texts:
I posted this question on the space exploration SE but people recommended that it would be more on-topic here. Could someone please help by giving some definite laws of nomenclature for celestial objects, like the provisional names given before a proper name is decided... I am copy-pasting the question here:
I tried searching the answer to this on Google for hours and visited the IAU website as well, but it didn't really clarify my doubt. I was reading about Black Widow Pulsar, which is an "eclipsing binary millisecond pulsar in the Milky Way" and after its common name, in brackets is given PSR B1957+20. How is this named? What nomenclature rules are used? Was this the provisional name given before it was named Black Widow Pulsar or is this the scientific name of the neutron star?
This is the case with most interstellar objects and stars. Like Ultima Thule has another name 486958 Arrokoth? Is this a scientific name? Please explain what nomenclature conventions are used to name the asteroids and stars.


texts: Open source library to calculate image from signals of a distributed set of radio dishes?

texts:
The National Radio Astronomy Observatory's Q&A "How To Make Images With a Radio Telescope" says

The most straightforward way to make a radio image with your satellite antenna system, then, is to use an array detector, which I believe would be very difficult to find.  Alternatively, one can make an image by pointing an antenna to an array of nearby positions on the sky then creating a contour map of the measured signal strength.  This is a rather slow process, though, that only produces an image much later, after you have gathered all of your individual pointing measurements.

Assume now that a lot of people all over a continent (e.g. Europe) would have (fixed, non-moveable) radio dishes pointing somewhere into the sky, with their field of view somewhat overlapping. They have different dishes and different receivers. However, given their exact location on the globe, knowing their exact time-stamp of observation, at least theoretically, I should be able to combine the measured time-series of radio-signals to a radio-image of the sky, correct?
The idea already bothers me a while and I am wondering whether there is some open source software I should be aware of to tackle the problem of caculating such an image, ideally in python (but possibly in any other programming language).
Any input is appreciated!
Related

Radio Astronomy and Imaging
In astronomical interferometry, what values do the points in the uv-plane have?
Can one build a distributed radio telescope?
How big a dish do I need for radio astronomy?


texts: Can an infinite universe explain the Fermi Paradox?

texts:
Explanation of potential problem:

We're not completely sure exactly how unlikely an event Abiogenesis was, given both the extreme unlikelihood of nucleotides randomly assembling into anything making sense and the vastness of primordial ocean and extent of time it existed. And still, despite their vastness, when involved with probabilistic chain of events we're quickly getting numbers by which planetary scale pales.

It may very well be that the event was unlikely enough to be nearly impossible not only on the planetary scale, but even on the galactic scale - or even on scale of the observable universe.

My proposed solution to this problem:

Regardless, with the actual universe being infinite, it would be bound to happen somewhere. Still, occurrences of life could be separated by many times the width of observable universe, and none of them could ever contact another.

...which would offer a possible explanation to the Fermi Paradox.

Does my proposed solution address the problem I outlined above, or is there a flaw in my reasoning/understanding?


texts: If a massive object like Jupiter flew past the Earth how close would it need to come to pull people off of the surface?

texts:
I understand this is a silly hypothetical but I'm asking for a 7 year old so please bear with me.

Imagine an interstellar stray gas giant comes flying through our solar system.

If we were not concerned that it would also steal our atmosphere and create tidal forces that destroyed everything... How close would it need to come to us to exert enough gravity to lift people off the ground and pull them into its own orbit?


texts: Do objects look larger the further away they are, beyond z=1?

texts:
I stumbled upon this text which illustrates and says:

  We find that as the object is moved to higher redshifts its angular
  size first decreases (as naively expected) but soon begins to increase
  after passing through a minimum value.

Is this correct for the mainstream standard model? What would an English language explanation be?


texts: dull rock/potato-shaped object seen with naked eye, moving in straight line during night. What could it be and is size and speed estimation possible?

texts:
Between years 2009-2011, I was located in Greece, watching the perfectly dark night sky around 21:00-23:00 during summer, when I suddenly noticed a very dull dark-brown object that looked like a solid rock/potato having a perceived size around half the diameter of the moon in the sky, moving in a perfect straight line looking up
 and perceived as fast (it took 3-4 seconds to disappear in the horizon) - so total exposure if I had seen it from start to end would have been less than 10-12 seconds.

One could barely notice it, it had some texture like a rock but blurry. It had almost no light reflection and it wasn't rotating or anything. It wasn't spherical and it was somewhat elongated along the axis of movement. I was barely able to detect it above me with naked eyes, as it was passing from left to right. I only did when I saw it was hiding a small region of the night sky stars. This way I perceived its irregular shape.

Unfortunately I cannot tell it's actual size or how fast it was going. Is it an object of a kind known to astronomers? I couldn't find any similar video footage or anyone seeing something similar talking in the internet. Could it be a space rock (asteroid?) that missed the earth atmosphere and at the same time be seen with naked eyes? Any estimates on space rock type, size and speed based on the time of sky exposure? Any astronomical id from a database or some guidance on how I could search it?
Could it be an asteroid occultation like this one: http://call4obs.iota-es.de/wp-content/uploads/2011/08/palma_south.gif
Thanks


texts: Long term temperature effects of an eclipse

texts:
I was surprised to see a very measurable difference in temperature at my home during the recent solar eclipse.  The temperature was about 93 degrees fahrenheit but dropped to around 86 degrees.  It made me wonder how an unusual eclipse might affect a planetary body.

If there were a situation where someone had put an object into a stable synchronous orbit that would block a percentage of solar radiation, how big would it have to be for an appreciable effect?  An example would be from Futurama's Crimes of the Hot episode Wernstom's giant parabolic mirror that reflected 40% of all sunlight.
If an effect similar to a solar eclipse would be prolonged over a specific area, how would that effect the local atmosphere?  I would assume it would create a stable "cold front" in that area.  Is there any information on how that would affect other passing cold or warm fronts?


texts: How was the Earth-Sun distance originally calculated?

texts:
AFAIK it was possible long before the first interplanetary probes.

Who did it?


texts: Why do planets move in an elliptical orbit?

texts: I am a student of class 9 and recently came to know about kepler's law of planetary motion and got confused about the foci and elliptical orbits of planets and some stars.


texts: I know that blue stars are the hottest and youngest (according to Universe Today). But what makes them blue, instead of other colors like purple?


texts: How have we measured the radius of the Earth (old and new)?

texts:
I'd imagine ancient methods are fun exercises in geometry. how has the measurement has evolved over time?

The first method is credited to Eratosthenes. He knew that during the summer solstice in Syenne the angle of the Sun overhead at noon was $0^\circ$. Following this he made the same measurement in Alexandria and measured the angle of the Sun overhead using shadows and calculated it to be $\approx 7^\circ$ which is approximately $1/50$ of a circle. Hence, both the circumference and the radius are easily calculated and quite accurate for such crude methods.


texts: How to calculate planetary position over vast time spans

texts:
Ignoring the turbulent beginnings of our solar system I wonder if there is a meaningful way to calculate the relative position of the planets of our solar system 100 million years into the future using the standard parameters
N /  i  /  w /  a /  e   /  M / +- pertubations , {assuming no unannounced black hole or neutron star zips through our solar system in the meantime.}
How far can the orbital calculations be projected into the future before error accumulation make these calculations completely meaningless?


texts: Why do satellites with greater altitude travel at a slower speed?

texts: For example, a geostationary satellite travels slower than the ISS. What is going on?


texts:
This answer says:

  Earth's orbital eccentricity varies over time from being nearly circular (low eccentricity of 0.0034) and mildly elliptical (high eccentricity of 0.058). It takes roughly 100,000 years for Earth to undergo a full cycle.

Why does the Earth's orbital eccentricity oscillate with a period of about 100,000 years? What would be the simplest set of conditions and/or fewest body system that would lead to this particular type of periodic variation in eccentricity?


texts:
just want to try to clarify a few things about the nature of White Dwarfs and degenerate gases.

So if a white dwarf is help up by an electron degenerate gas, the electrons are unable to lose energy by emitting photons, correct? They basically are trapped at whatever energy level they occupy and that's that. The nuclei that make up the majority of the mass of the star are still constituents of a "normal" gas however, correct? This means that these nuclei and emit photons to lose kinetic energy? How does that work exactly? I understand that electron can emit photos inside an atom to drop to lower energy levels and that they can emit photons of any energy level if they are free (particularly if they're in a magnetic field, synchroton radiation, yeah?). To protons and neutrons do something similar? I ask because I never read anything about protons/nuclei emitting photons. If this basic picture is correct, is this the mechanism by which a white dwarf cools down over time?

Final bit, since most white dwarfs are quite hot, the peak wavelength is going to be in the UV. If I wanted to determine the percentage of such a star's luminosity that is given off in the optical, do I just need to integrate Planck's blackbody equation over the range of wavelengths I'm interested in and then compare that to the total luminosity given by $L = 4\pi R^2 \sigma T^4$?

Thanks and Cheers!


texts: What would happen to Jupiter if a brown dwarf star collided with it, and vice versa what would happen to the brown dwarf star?


texts:
The Great Red Spot is an anticyclonic storm on Jupiter that is bigger than the Earth. Based on the Wikipedia article, it has been shrinking in size for the last 400 years, going from 41 to 16 thousand kilometers wide. What is causing this shrinking?
These articles (1, 2) talk about the spot shrinkage, but are rather vague on the causes. Both of them mention that we will likely learn more with the Juno probe. Now that we have data from Juno, do we know more about why the Great Red Spot is changing in size?


texts: Power requirement for transmitting communications further than 1 ly?

texts:
The StarShot project from Breakthrough Initiatives aims to send a paper light spacecraft to alpha centauri using pressure from a laser located on earth at 20,000kms.

What are the options for a transmitter that can be received from 1-4 lyrs away, if the transmitter weighs the same as a few jellybeans (<10 grams)? What wavelength and power range can they work with for that distance using that weight of equipment?


texts: What (actually) does "peculiar periodic spectral modulations" refer to in this preprint?

texts:
I saw this ArXiv preprint after reading about it in the popular media.
I can not even understand the beginning of the introduction (much less the whole paper):

INTRODUCTION
A Fourier transform analysis of 2.5 million spectra in the Data Release 8 of the Sloan Digital Sky Survey (SDSS) and the SEGUE 2 SDSS was carried out to detect periodic modulations contained in their frequency spectra (Trottier 2012).

where Trottier 2012 is Recherche de signaux périodiques dans des spectres astronomiques, M.Sc. Thesis, Université Laval
The modulation frequency seems to be of order 10${}^{-12}$ seconds, and the SDSS is (as far as I know) not really a particularly time-resolved data set. 1 micron wavelength light (for general reference) has a frequency of about 3x10${}^{-14}$.
I'm not asking (necessarily) if this result is right or wrong, I'd just like to understand how the SDSS can actually be analyzed to detect or even infer THz rate modulation!


texts: Is there an oxide layer on aluminum reflectors for telescopes?

texts:
I was watching a Nottingham Science video linked here (periodic videos) and they mention modern reflectors are made of aluminum.

I can understand why mirrors are preferred over lenses, but what inhibits the aluminum oxide coating that would naturally form on the surface of the mirror? Why do they work so well?


texts: The equation for calculating how many times Earth (or our solar system) has revolved around the Milky Way

texts: I have seen it said on Quora and Reddit that it's about every 220-250 million years to go around the Milky Way from Earth. Wondering what the rough equation is for calculating it. That is, I guess, the angular momentum and distance from the center, so I could visualize it on a sped up animation and otherwise derive something like those numbers 220 to 250.


texts:
"The Universe is commonly defined as the totality of existence" but that is more of a philosophical position. Empirically we know (or believe) that it is of finite size some believe it is expanding others that is (or will be) contracting.

As we gain knowledge about distant places, our scope of area has expanded from Planet, to Solar system, to Galaxy, to Universe. In the same way we continue to find smaller and smaller building blocks, from Elements, to Atoms, to Quarks.

It is reasonable to assume, that the same gains in knowledge the removed the burden from Atlas, will find the edge of the Universe, and something that is beyond that edge.

What is the name of that which exists beyond the Universe?

Naysayers, who may claim that there is "nothing" beyond universe, are reminded that their beliefs are no less strong than, those who claimed that "nothing" was supporting the Turtle or the Elephant who like Atlas also supported the world.  Lack of knowledge does not mean lack of existence.


texts:
I'm researching a scene for a sci-fi novel in which the near-future protagonists observe earth through a station-mounted telescope in Mars orbit. My goal is to understand how much detail they reasonably could discern.

The Hubble telescope is probably a reasonable comparison for my purposes. I found images Hubble took of Mars during a close approach, but I don't know if those represent the best resolution possible or simply the resolution that was selected or available at the time, or indeed, if the whole planet was imaged at a higher resolution than the photo published in popular media outlets.

Can a Hubble-like telescope observe significantly greater detail than displayed in the article below? If so, what might reasonably be resolved? Large cities? Individual buildings?

From Vox.com's Hubble can see galaxies impossibly far away. Here’s what happens when it looks at Mars and Saturn.

above: Cropped from Source NASA, ESA, and STScI

above: Cropped from Source NASA/Hubble


texts: Can astronomical radio sources be used as a verifiable randomness beacon?

texts:
A randomness beacon is a source of random data that is broadcast to multiple parties. Users listening to the beacon receive the same sequence of random strings and no one can predict the values in advance. This is a construct that has many applications in cryptography and distributed communications. Such random sequences have been generated using atmospheric noise, quantum measurements, and financial data (*).

Using astronomical radio sources (such as meteor bursts, solar noise, planetary observations, CMBR, etc.), is it possible for multiple independent observers spread around the globe, using relatively inexpensive equipment, to detect the same unpredictable cosmic signals, and agree on the time and properties of those signals (to within some margin of error)?

If this were feasible, you could create a publicly-verifiable randomness beacon that didn't require trusting a central authority to generate the sequence in an unbiased way. Instead, observers can certify the random values independently using their own local measurements.

(*) usenix dot org /legacy/events/evtwote10/tech/full_papers/Clark.pdf


texts: How to use the APARM, BPARM and CPARM of REGRD task in AIPS?

texts: I plan to regrid a 500 by 500 image in B1950 to 500 by 500 in J2000 using the AIPS task REGRD. How to proceed?


texts: Questions about a fictional binary system, and habitability

texts:
Note: Questions are at the bottom. The rest had simply been written in a format to better organize my thoughts. The formulas used to construct this fictional solar system, had been borrowed from Artefxian and are presented in several of his videos.

Theoretical:
A P-Type binary star system featuring a gas giant on or near the habitable zone, with a habitable moon.

Considerations:

Gas giant would need a stable magnetosphere. Jupiter and Saturn may be useful examples.
The moon's mass must be great enough to sustain an atmosphere. In this instance, a nitrogen/oxygen atmosphere. It is estimated that a moon with a mars-like density, would need at least 7% of Earth's mass in order to support such an atmosphere for several billion years.
Both gas giant and the habitable moon must maintain stable orbit. Simulations would suggest that, to maintain a stable orbit to a gas giant, or a brown dwarf that orbits 1 AU from a sun-like star, would require a moon orbital period of less than 45 - 60 days.
The moon itself must be capable of generating it's own magnetosphere in order to deflect stellar wind and the gas giants' naturally generated radiation belts.
There is a high likelihood that the moon would be tidally locked with it's parent world. Monoj Joshi, Robert Haberle, and their colleagues suggest that the effect of tidal heating could support conditions amenable to habitability. Additionally, tidal effects may allow for plate tectonics, causing volcanic activity and a regulation of the moon's surface temperature. The potential, resulting geodynamo effect would allow for a strong magnetic field.
Balance: The moon should be large enough to support tectonic activity, dense enough to support a strong protective magnetosphere, close enough to the gas giant to maintain stable orbit, and be far enough away that it's own magnetosphere may better protect from sputtering caused by it's parent worlds' radiation belts.
It is suggested that the larger and more dense a terrestrial, water-rich world, the further out it's habitable zone extends.

Fictional Data:
Star A: Mass = 1.1; Luminosity = 1.39; Diameter = 1.07; Surface Temperature = 1.04
Star B: Mass = 0.9; Luminosity = 0.69; Diameter = 0.92; Surface Temperature = 0.94
Separation: 0.3 AU
Barycenter: 0.45/0.225 AU
Eccentricity: 0.4/0.5
Separation Minimum: 0.27/0.1125
Separation Maximum: 0.63/0.3375
Separation Overall: 0.9/0.45
Inner Boundary: 0.2 AU
Outer Boundary: 80 AU
Frostline: 6.984 AU
Inner Habitable Zone: 1.976 AU
Outer Habitable Zone: 2.808 AU
Ideal Position: 1.8 AU
Inner Forbidden "Hell" Zone: 0.3 AU
Outer Forbidden "Hell" Zone: 1.35 AU

Goal: Create a fictional, theoretical system which can be demonstrated as stable, in which an earth analog may safely orbit a gas giant.

Further Considerations:

The moon does not necessarily need to be an earth analog, and may simply be demonstrated as habitable to human life.
The gas giant does not necessarily need to be within the habitable zone, and may cradle the outer limits of the CMZ, or be further out provided it can be demonstrated that the orbiting moon could feasibly support human life unassisted by technology. i.e. Robin Crusoe could become stranded on the moon, and survive.

Questions:

How far would the moon have to orbit from it's parent body, to prevent tidal locking?
How can I find a balance, between the binary stars' gravitational pull, the gas giant's gravitational pull, and the chaos it may play on the moon?
If no balance can be met, I will accept tidal locking with the moon. In this instance, how can I go about determining a safe and stable orbiting distance for the moon?
How can I determine the effect of the gas giants' magnetosphere on the moon? What would the math behind it look like?
Are there any considerations I may be missing, and how would they affect this scenario?


texts: The electron–cyclotron maser emissions from Earth

texts:
The first-ever detection of radio signals caused by the electron–cyclotron maser mechanism outside of the Solar System, on Tau Bootis b was recently published (here). This phenomenon causes huge radio emissions from Jupiter, for example, due to the enormous amount of plasma ions from Io. On Earth, I suppose, this phenomenon still happens, due to the plasma radiation of the Sun on Earth ionosphere.
My question is: how strong is it and how it's compared to Tau Bootis and Jupiter?


texts: Is there an equivalent of the red shift effect for cosmic rays?

texts:
I had read somewhere that light from very distant sources can be measured to be increasingly red shifted the further away the object is (due to cosmic inflation?).
Suppose you had an object emitting cosmic rays or neutrinos other physical matter (not photons), is there an equivalent effect for these objects? ex: a red-shifted helium nuceli in a cosmic ray or red-shifted neutrinos coming from a neutrino source?


texts: Ratios of magnitudes instead of differences

texts:
The color index in the photometric system is defined by the differences in magnitudes between two wavelength filters, which gives the ratio of intensities. For example, to determine the B-V index, you'd need the magnitudes in the B band (which is centered on $\lambda = 445$nm) and in the V band, centered on $\lambda = 551$nm.

But what about other operations? For instance, would there be any significance in taking, say, the ratio $B/V$ or $B\times V$?


texts:
As far as I can see, there are two main sources for the emission of energy from an accretion disk:

release of gravitational potential energy of the infalling matter;
friction from differential rotation within the disk.

How much of the emitted energy is due to each process? For that matter, are there any other processes that contribute to the spectrum?


texts:
How bright are geostationary satellites due to reflected sunlight? and Did Sputnik 1 tell us more than “beep”? What science was improved by information gained from its orbiting the Earth? now have me wondering how bright and visible Sputnik 1 would have been.
Sputnik 1 was a smooth, shiny, reflective metal sphere 58 cm in diameter with an initial periapsis and apoapsis of about 200 and 900 km altitude.
Vanguard 2 was similar, with a 51 cm diameter and a 560 x 2,953 orbit.
Normally we treat asteroids with an albedo and some  model for diffuse reflectivity based on phase angle. See answers to the questions linked below.
But in this case it's probably a good approximation to use geometrical optics and assume specular reflection. The problem is that I don't know how to do that!
Question: Apparent magnitude of a spherical body with specular, rather than diffuse reflectivity? How bright were Sputnik 1 and Vanguard 2?

Calculating the apparent magnitude of a satellite
Why is Enceladus's albedo greater than 1?
What is the difference between albedo, absolute magnitude or aparent magnitude?
When would we detect a tiny meter size natural satellite in a geostationary orbits?
Venus' magnitude during inferior conjunction

Screen shots from the PeriscopeFilm video "Science in Space" Early 1960's Space Exploration Film Sputnik & Explorer Vanguard Rocket 12494 The photographic negative contains an image of Vanguard 2 from a tracking camera. Click for full size:


texts: Would a tidally locked planet be always increasing in temperature?

texts: Okay, say we have a tidally locked planet that has one side facing its star. On the side that always faces the star, my question is will that side facing the star always be increasing in temperature? If the side is always facing the star, it doesn't have time to cool.


texts: How can we use hypervelocity stars to determine the origins of the Universe?

texts:
I was reading this article finding evidence of Universe's origin, which describes that in 1 trillion years we may lose the ability to determine how the universe was created.

The answer seems to be using hypervelocity stars.  These are stars that have been ejected from their galaxy.  Using the expansion of the universe, we can use the velocity of the star to then determine evidence of the Big Bang. But how does this work?  Is there calculations we can do now that agree with our understanding of the universe and its age when working with hypervelocity stars?

I understand finding a hypervelocity star is very hard to do. I guess my thought here is that astronomers have modeled this scenario and found that if we were to find a hypervelocity star, we could then use the scenario above to calculate the age.  I'm assuming the age calculated agrees with current estimates.


texts: Are features in the CMB correlated with features in the SDSS map of the most distant galaxies?

texts:
This is a follow up to an earlier question to which @pela gave an excellent answer. Apparently the statistics of the length-scales of the CMB fluctuations are similar to those obtained from other measurements.
This question is more specific in asking whether any of the structures observed in the CMB are also observed in the distribution of the most ancient galaxies such as from the Sloan Sky Survey SDSS.  So this is specifically asking whether there is a significant positive cross-correlation between between the different measurements (rather than whether their autocorrelations are similar).


texts: Why does the Event Horizon Telescope (EHT) not include telescopes from Africa, Asia or Australia?

texts:
The Event Horizon Telescope seems to include these radio telescopes currently:

Image by European Southern Observatory (ESO)/O. Furtak; CC-BY 4.0-licensed, see the source on Wikipedia Commons and the original image link.

See also the map and list on their official website.

It is also said, that it has a “effective diameter of the entire planet”.
But it's striking, it does not include half-of the earth… It has no telescopes in Africa, Asia or Australia.

So:

Why were not they included?
Would it increase the diameter if they would include some from there? If so, again why did not they? ()
Or, similarly asked: How can it be the diameter of the earth if only half-the-earth is included in the network?

Please try to explain it in a simple way first. I am no astronomer.

What I've noticed so far when skimming their official pages is that they write here:

  As more telescopes are added to the EHT, we will be able to produce images of the emission around black holes. In general, the fidelity of images produced by an interferometric array increases as additional telescopes are added to the array.

This seems to support my question of why they did not use possibilities in Asia or so…
I guess, it would also make sense to have a more or less uniform distribution across the planet (or does not this matter?), that's why a "dot" in Africa might make sense too…


texts:
Excluding 'fluffy' or 'puffy' gas giants that are 'inflated by heat from their stars, what is the maximum radius of a gas giant planet.  I keep reading things like "...Jupiter is 'about' as big as they get...", but I can't seem to find a specific number to go with that word "about".

Assuming a gas giant was made up of the highest plausible ratio of Hydrogen, and the lowest plausible ratios of other elements (and not significantly heated by the star), just how big could a gas giant get before it started shrinking again under its own weight/gravity?

Is it really just 1 Jupiter radius? 1.0001? 1.1? 1.3?


texts: Translating a zenith position to the nadir

texts:
What would be the easiest way to translate a zenith position to a nadir on the celestial sphere?
For example I have a position from the azimuthal grid in Stellarium; 3h44m32.64s/+50°50'16.2"
which was obtained based on my location at +50°54'13.9" -2°34'19.1" and a time of ; 15/03/2019 16:24:20.


texts: What is the cycle for when the maximum amount of the Moon's apparent area is sunlit?

texts:
The Moon is defined as full when its ecliptic longitude is 180$^{\circ}$ distant from the Sun's.

But what is the cycle for when the maximum proportion of the moon's apparent area is sunlit, and for observers at what latitudes of the Earth's surface is this maximum realised?

Notes

1) After first guessing (on this expert Q&A site) that the answer is "one lunar month" and asking me whether there was "a reason" why the said cycle might be different from it, user UhOh has requested clarification of the term "moon's apparent area", pointing out that the moon has a rough surface. The difference of the apparent perimeter of the Moon's disc from a circle does not have a bearing on the answer to this question that is of anything like the magnitude of the contribution made by the 5$^{\circ}$ tilt of the plane of the Moon's orbit around the Earth relative to the plane of the Earth's orbit around the Sun. Please ignore mountains and craters. Please assume either that the Moon is a sphere, or if you wish then take it to be a spheroid with an eccentricity of about 1/900. The question is about the relative movements of the three celestial bodies concerned. (If further clarification is required of any other term used, please let me know.)

2) Wouldn't it be great if there were a website where you could input your latitude and longitude and desired start date and end date and get a graph of the proportion of the moon's apparent disc that is sunlit from your location? But I don't think this exists (yet!)


texts: Is Spherical Astronomy by W. M. Smart a good book on positional/spherical astronomy?

texts:
I'm a math undergrad, but I'm really interested in learning positional astronomy; However, the only well-referenced textbook I've come up with is Spherical Astronomy by W. M. Smart.

I would like to understand how suitable it is today. I have the 6th edition which seems to be the latest, but which was issued back in 1977. I know that a relatively old math text book, for example Apostol's Calculus (published in the 60's, if I'm not wrong), won't present too much trouble, but I'm a newcomer to astronomy, so I don't know if a book printed in 1977 is "up to date".

Given the case that there are better or more up-to-date books, are there other recommended texts for me to read as well or is this one a good choice?


texts:
I know larger stars can fuse heavier and heavier elements up to iron where it stops because fusing iron requires more energy than it releases, causing a collapse and supernova.

Why does fusing iron in a stellar core use more energy than it releases?


texts: How can black holes spin if they're singularities?

texts: How can black holes spin if the event horizon isn't a surface but just the border between where light can escape and where it can't? A black hole is assumed to be a singularity or the "entrance" of an Einstein Rosen Bridge (while white holes are the "exit" of one) so how can it spin and how can you tell how fast it spins (on its event horizon or whatever)? Isn't it rather the accreted material that is spinning around the black hole?


texts: Are falling evaporating bodies (FEBs) and exocomets the same thing? How does one know they're falling and evaporating?

texts:
Looking for a (short) list of comets with heliocentric escape velocity I stumbled upon Wikipedia's exocoments which like exoplanets, are bound to other stars. I should have been looking for "rogue comments".
That aside, looking at the abstract of Transiting exocomets detected in broadband light by TESS in the β Pictoris system (and in arXiv):

We search for signs of falling evaporating bodies (FEBs, also known as exocomets) in photometric time series obtained for β Pictoris after fitting and removing its δ Scuti type pulsation frequencies. Using photometric data obtained by the TESS satellite we determine the pulsational properties of the exoplanet host star β Pictoris through frequency analysis. We then prewhiten the 54 identified δ Scuti p-modes and investigate the residual photometric time series for the presence of FEBs. We identify three distinct dipping events in the light curve of β Pictoris over a 105-day period. These dips have depths from 0.5 to 2 millimagnitudes and durations of up to 2 days for the largest dip. These dips are asymmetric in nature and are consistent with a model of an evaporating comet with an extended tail crossing the disk of the star. We present the first broadband detections of exocomets crossing the disk of β Pictoris, consistent with the predictions made 20 years earlier by Lecavelier Des Etangs et al. (1999). No periodic transits are seen in this time series. These observations confirm the spectroscopic detection of exocomets in Calcium H and K lines that have been seen in high resolution spectroscopy.

It's this part of first sentence that caught my eye: "falling evaporating bodies (FEBs, also known as exocomets)". "...also known as..." (also known as "aka") to me implies a 1:1 mapping, but maybe I'm wrong.

Are all "falling evaporating bodies" also exocomets?
Are all exocomets also "falling evaporating bodies"
How does one know if a light dip is from a body that is falling, or evaporating?

note: I've use the comets and exoplanet tags because we don't have an exocomet tag.


texts:
The Ulysses mission has a compelling story. It was sent to Jupiter to perform a gravitational assist shooting it out of the plane of the ecliptic in order to fly over the Sun's north and south poles to perform "fast latitude scans". Because of its design it was used for several important lines of scientific study.
Ulysses contained a pair of coherent transponders which received signals from Earth, shifted them in frequency in a coherent way using phase-locked loops and beamed them immediately back to Earth at two different frequencies.
From ESA's write up of the Ulysses Gravitational Wave Experiment:

In the spacecraft Doppler tracking method, the Earth and spacecraft constitute the two objects whose time-varying separation is monitored to detect a passing gravitational wave. The monitoring is accomplished with high-precision Doppler tracking in which a constant frequency microwave radio signal (S-band) is transmitted from the Earth to the spacecraft (uplink); the signal is transponded (received and coherently amplified) at the spacecraft; and then transmitted back to Earth (downlink) in both S- and X-band signals. This Dual frequency downlink is required in order to calibrate the interplanetary media which affects the two frequency bands differently. The downlink signal is recorded at Earth and its frequency is compared to the constant uplink frequency f0 to extract the Doppler signal, δf / f0.

The article goes on to say:

Since the optimum size of a gravitational wave detector is the wave length, interplanetary dimensions are needed for detecting gravitational waves in the mHz range. Doppler tracking of Ulysses provides sensitive detections of gravitational waves in this low frequency band. The driving noise source is the fluctuations in the refractive index of interplanetary plasma. This dictates the timing of the experiment to be near solar opposition and sets the target accuracy for the fractional frequency change at 3.0 × 10-14 for integration times of the order of 1000 seconds.
SUMMARY OF OBJECTIVES
The objective of the gravitational wave investigation on Ulysses is to search for low frequency gravitational waves crossing the Solar System. Because of the great distance to the spacecraft, this method is most sensitive to wave periods between about 100 - 8000 seconds, a band which is not accessible to ground-based experiments which are superior for periods below 1 second.

You can read more about Ulysses in eoPortal's Ulysses where I found both the link above and the following:
B. Bertotti, R. Ambrosini, S. W. Asmar, J. P. Brenkle, G. Comoretto, G. Giampieri, L. Iess, A. Messeri, H. D. Wahlquist, “The gravitational wave experiment,” Astronomy and Astrophysics Supplement Series, Ulysses Instruments Special Issue, Vol. 92, No. 2, pp. 431-440, Jan. 1992

Question: What produces gravitational waves with "periods between about 100 - 8000 seconds"?


texts: Was there ever a Jupiter transit or Saturn transit?

texts:
I've watched the Venus transit 2004 with a small telescope, a relatively rare event, considering most people can only observe two in their life time.

If E.T. were sitting in a sunny place on a moon of the outer planets,
sipping on a liquid nitrogen drink, would there ever be (has there ever been) a transit of an inner gas giant?

I guess if E.T. were in Sputnik Planum, there would be no transits due to Pluto's orbital plane being inclined too much wrt. the Ecliptic.


texts:
two years ago I grabbed an XML star catalogue of the zodiac constellations that came in the following format:
<star>
    <id>1</id>
    <name>Sadalsuud</name>
    <desig>22 Bet Aqr</desig>
    <hip>106278</hip>
    <hd>204867</hd>
    <sao>145457</sao>
    <con>Aqr</con>
    <mag>2.9</mag>
    <dist>611.94</dist>
    <rad>6.5</rad>
    <spk>G0Ib</spk>
    <bvc>0.837</bvc>
    <teff>5700</teff>
    <mass>6.25</mass>
    <radius>50</radius>
    <ra>21.525979</ra>
    <de>-5.571155</de>
</star>

Sadly I forgot where I took them from.
Does somebody recognize this format or can recommend where I can get the stars of the constellations in a similar format?
Thank you!


texts:
I'm interested in knowing how low the sun could ever get in the sky and still be seen.

More technically: what's the minimum possible elevation of the sun at which it can still be seen above the visible horizon from a terrestrial vantage point?  And where on Earth would you go to make such an observation?

Some clarification:

elevation is angular distance measured from the astronomical horizon (the great circle that is 90° from the local vertical).

For example, I imagine from a mountain top near the ocean, you might be able to view the sun at an elevation angle that is negative, below the astronomical horizon but above the visible horizon, and possibly by a decent amount.  So then I thought Mt. Everest might be the spot, but locally I'm not sure how low the visible horizon is, because the surrounding area is at a high elevation too.  So maybe I'm just looking for the highest angle possible between mountain peek and sea level, in other words, where is the lowest apparent visible horizon, but the sun may not necessarily ever rise or set in that direction.

I also looked around for a map of local visible horizon angles (measured relative to the astronomical horizon), but couldn't find one.  I suppose such a thing could be constructed from a topographical map of the Earth, right?  Maybe this would be the best way to "solve" this if nobody already knows.

I'm hoping the answer can ultimately be turned into a factoid of the following format (looking to fill in the unknowns in this):

  "From the top of mount something-or-other, looking west, the visible horizon is x° below the astronomical horizon.  From this vantage point, just before sunset, the edge of the sun could be observed to be f(x) sun diameters below eye-level."


texts: Interstellar movie: What is the "portal" to the other galaxy?

texts:
I recently watched Interstellar with some friends and we didn't come to the same conclusion. In my opinion, the portal they use to go to the other galaxy (to visit the three planets) is not a black hole. My friends tell me it is.

(warning, contains spoiler!!)

To me, it's not because of these points:

When they are in front of the portal, they can see the other galaxy, which is not the case when Coop goes to the black hole at the end
When they go to that portal, they "flow" in a tube like channel. Again, that's not the case when Coop goes to the black hole at the end.
When Coop goes to that black hole, he goes through some sort of light dust that hits his ship, which is not the case when they go to the portal.
When the robot (I forgot his name) goes in the black hole, his purpose is to collect some quantic data. If the initial portal was also a black hole, he would have made that collection at that time.
When they goes to the portal, they seems "confident", but when Coop goes to that black hole, it's for killing himself. If the portal was a black hole, they would behave more identical.

So I believe it's not a black-hole, but what is it exactly (maybe not in scientific terms, but in Interstellar's terms)? A Wormhole?


texts: Line of lights moving in a straight line, with a few following

texts:
My husband and I have just seen a line of about 15 lights moving in a straight line, quite high above the cloud level with a gap, and then 5 lights, a gap, another few, a gap, 1 light, a gap, and a few more.

They were moving at the same sort of speed as I would expect a plane to move at - almost like a train in the sky with a banner flying behind. They were in the sky for at least a minute.

I had seen a shooting star a few minutes before and it wasn’t one of them... what could it be?

Could it be Elon Musk’s satellites?


texts: What escape velocity would quark stars have?

texts: Quark stars are hypothetical compact stars that are denser than neutron stars and maybe the last stage of upholding matter before stars that collapse into a singularity. Neutron stars have escape velocities up to half the speed of light, and the escape velocity of quark stars must be even closer to c. Could it be that some or all black holes are quark stars whose escape velocity is just above 1 c, rather than singularities?


texts: What is visible light colour output of different stars?

texts: I know the colours of the stars relate to their heat, however if I were standing on a different planet identical to Earth, but orbiting a blue Bright Giant or a Red Giant, or perhaps even a Red Dwarf, what colours in visible light would I be able to see? Is it the same as with our star, i.e. would any be missing such as if I'm in a room with a black light?


texts: How much is the zoom of Sun-Pluto eclipse image

texts: The Sun-Pluto eclipse picture was taken from 2 million km from Pluto. At that distance, Pluto will have angular size of just 4'5". Hence this picture must be a zoomed up image. Approximately how much will be the zoom of this image? Also, is it possible to give the power of its camera in megapixel terms? Thanks for your responses.


texts: How large would an asteroid have to be in order to hold a person so that the person could not escape?


texts:
I understand Planetary Eccentricity and Inclination.  However when it applies to a star, does the centre or ecliptic plane refer to the Sun or the Galactic Centre?

The star Sirius for example, 136.336 ± 0.040° inclination, the angle at which it is inclined to Sun, Earth or Galactic Centre?

The star Sirius has an Eccentricity of  0.59142 ± 0.00037.  The only thing the star orbits is the Galactic Centre (Sagittarius A*) so I guess that is the centre?


texts:
I am confused with nucleosynthesis inside supernovae. I have read that the heavier elements are made through fusion of lighter element's namely hydrogen and helium.

Does the star "store" all the elements they fuse inside themselves or are they radiated out?

Example, A star fused hydrogen into helium and 2 helium atoms into carbon. Would it keep fusing until it hits the limit and store it inside only to be released as an explosion.


texts: How are non-visible electromagnetic waves detected that originate from space?

texts: How are non-visible electromagnetic waves from space detected and interpreted by the receiver? Is it in the same manner, as say radio waves produced on Earth, where the EM wave interacts with the telescope antennae and causes electrons to oscillate and as such is recorded as an electrical signal which can then be interpreted as an image?  I have tried to research exactly how the receiver converts EM waves into a "signal" we read but generally, information just states that the em wave is detected, amplified, and stored by a computer.


texts: Why aren't new stars in Earth's relative proximity constantly discovered?

texts:
Okay, bear with me. In layman's terms:

The estimates vary, but on a clear night, away from big cities, one can see up to 5000 stars in the sky. All those are in the Milky Way, but they're hardly equidistant from Earth, which would mean that they revolve around the galactic center at different orbits. According to some sources, some are positioned very closely to us while others hang out as far as 1000 light year away.

Now by astronomical standards, 5000 stars is not a great number. It's still pretty impressive, though.

Some stars are larger, and others are smaller. It stands to reason that some of them might be "hiding" behind others. Because they all orbit the galactic center at different speeds, using different orbits, wouldn't it follow that from time to time, over the centuries, decades, or even years (months?) a "new" star would emerge from behind another one? Shouldn't this be happening often; or are they so sparsely distributed around the galaxy that no "new" stars have appeared out there over the past three thousand years or so?


texts: How can you tell the rough phase of star formation a star is in from the current radius and mass of the star?

texts: This question is really bothering me since I'm getting mixed thoughts. The masses of the stars in question are 0.92 solar masses and 0.29 solar masses. The diameters are 1,400,000 km and 750,000 km respectively. Personally, I think they're regular main sequence stars and are not in a intermediate stage of star formation, but I'm unsure about this. Is there a method that can be used to figure out the rough phase of star formation that this star is in?


texts: How is the roll of the Hubble telescope around its axis and the dispersive direction(s) of it's spectrometer(s) managed?

texts:
Reading Dupree et al. 2020 Spatially Resolved Ultraviolet Spectroscopy of the Great Dimming of Betelgeuse (also in arXiv and summarized in Phys.org's Hubble finds that Betelgeuse's mysterious dimming is due to a traumatic outburst) it finally dawned on me that at least in the UV Betelgeuse is so big and close that it can be barely resolved by a single 2.4 m aperture in space, at least in the UV!
At 280 nm the Rayleigh criterion is 29 mas and the star's disk is probably 1.5  times larger than that (~44 mas). Of course the paper's spatial resolution applies to the much larger halo of material around the star.
Figure 3 shows the visible and UV continuum disks and the orientations of the 25x100 mas slit and dispersive direction for each of the observations discussed. I noticed that for all except one the dispersive direction was at either about +90° or -90° relative to the star's rotational axis, but one of them (2019 Nov 28) was off by roughly 36° from the average of the other seven (also see Table 1).
Questions

How is the roll of the HST around its axis and the dispersive direction(s) of it's spectrometer(s) managed? Can observers request any orientation as a standard part of their observing time, or is a special request necessary and a penalty in time and/or cost for not using whatever orientation the telescope is in at the time?
Is there any hardware that can rotate the spectrometer's dispersive direction relative to Hubble's axis internally, or does one always need to specify the orientation of the whole spacecraft?


texts: Lucky imaging with Celestron 14 - is this result reasonable?

texts:
I attempted to do some lucky imaging of Jupiter using a permanent installation (Celestron $14$" SCT + Paramount ME II) and Nikon D5600 attached directly to a Baader Hyperion 8-24mm eyepiece (without a filter). The atmospheric conditions weren't ideal ($65$% humidity, $2$ m/s winds), the telescope was properly acclimated prior to use, and Jupiter was around $17^{\circ}$ elevation during imaging.
After processing $3600$ frames (from 1 minute of video1 at $60$ fps) with Autostakkert 3 and then aligning the RGB channels and recomposing I got these:

Left (or top if your screen is small) is using $20$% of the stack, right (or bottom) is using $50$%. Since this is my first foray into planetary imaging my question is: are my results reasonable given the setup used and atmospheric conditions described?2
I'm asking because I've seen much better results from people using smaller telescopes. I think the discrepancy is the result of one (or several) of the following:

Something is wrong with the equipment I used.
I'm using the wrong equipment.
I'm not processing the images correctly.
This is the best the equipment could do under those conditions.
I did something wrong in my setup or imaging.

and I'm trying to rule out number 1.

Here is a single, unprocessed frame for reference:

 Update
I have acquired a Bahtinov mask to rule out the focus as the issue, here is an exposure of Manubrij (Omnicron Sagittarii) with the mask:

At the time of imaging, the angular separation between Jupiter and this star was less than $6^{\circ}$. Conditions were much better this time, humidity was $38$%, winds were less than $1$ m/s. The telescope was acclimated for about 2 hours prior to use.
Again using $3600$ frames af $60$ fps I got these:

Left (or top) is with $10$% of the stack, right (or bottom) is with $20$%. This looks slightly better to me, but I'm still not sure if this is what I should expect from the equipment.

1 Note that the video in the link has been compressed through ffmpeg using the H.265 codec with CRF of $25$.
2 This result is just one example - I did $30$ minutes of imaging in $3$ minute segments over the course of several hours, applying the same process to other sets of exposures yielded similar results.


texts: Does the Milky Way's movement through space have spacetime implications?

texts: The way I usually see spacetime explained, it says that if you just sit still, you are moving at 0kph and so you are moving at maximum speed through time (ie. time for you is flowing at maximum speed).  However, sitting still we're moving at the speed of our galaxy through space, which is about 600km/s.  The speed of light is about 300,000km/s.  So for simplicity's sake, let's say the galaxy is actually moving through space at 1,000km/s.  Does this in fact mean that if I sit still on Earth, time for me is actually flowing 1/300th slower than if I were sitting still with respect to the universe?  And does it also mean that if the Milky Way were travelling at 99% the speed of light, time for me would be flowing at 1% the rate of the flow of time for someone that was sitting still with respect to the universe?


texts: Is there any planet/star bigger than VY Canis Majoris?

texts: Compared to VY Canis Majoris, our Sun is more like a speck of space dust. Is there any planet or star which is known to us that is bigger than the VY Canis Majoris?


texts: Questions on apparent motion of superior planets

texts:
Question
Why is it that superior planets seem to oscillate up and down of the ecliptic, from the view of an observer on Earth, with a period equal to the planet's orbital period?
Additionally, why do these superior planets seem to come closer to the ecliptic when they are nearing conjunction and drift away from the ecliptic when they are near opposition?
Attempt
Does it have to do with the Earth's tilt?


texts: Can I build a telescope with a lens from a CD-ROM as eyepiece?

texts: I saw some article on the web about making an eyepiece of a telescope with the lens from a CD-ROM. Will this really work? I have an objective lens of 100 cm focal length. What will be the magnification if I could make a refractive telescope? Can I see the planets and moon with that? Can anyone suggest the arrangement of the lenses?


texts: How do astronomer measures the size of any celestial objects?

texts: What techniques and tools are available to the astronomers to measure the size of any celestial objects such as, stars or perhaps black holes that doesn't emit light nor reflects starlight?


texts: Musk's Roadster is now Russell's Teapot?

texts:
Space Exploration Stack Exchange were not very fond of this question and closed it, so I think it might fit better here.

Summary: Assuming no foreknowledge of its existence, can Elon Musk's Tesla Roadster be detected and categorised from Earth?

Bertrand Russell argued the following, an argument that is now known as Russell's Teapot (emphasis mine):

  Many orthodox people speak as though it were the business of sceptics to disprove received dogmas rather than of dogmatists to prove them. This is, of course, a mistake. If I were to suggest that between the Earth and Mars there is a china teapot revolving about the sun in an elliptical orbit, nobody would be able to disprove my assertion provided I were careful to add that the teapot is too small to be revealed even by our most powerful telescopes.

Well now we have a midnight cherry red automobile, between Earth and Mars, in an elliptical orbit around the Sun.

Now assume that this civilisation we have falls. The knowledge of this automobile is lost. Then in some centuries/millennia later humanity has managed to work its way back to a level of technology comparable to what we have today.

Could this automobile then be detected by "our most powerful telescopes"?

I guess that we could detect it as an orbiting object; it is large enough to be found. Can you confirm or refute this guess?

And if the automobile can be found as an orbiting object, could it then be determined that this is not an ordinary space rock, but that there is something very odd about it? That is to say: is it possible to do any kind of characterisation of the automobile that makes it stand out as an unusual space object. There is some uncertainty about the exact state of the automobile after such a long time, but there is no question that chemically and optically, this will be no space rock, even in several thousand years. The question is if we can detect that.

Digging some more I found about the (re)discovery of J002E3, which turned out to (probably) be the Apollo 12 Saturn-IVB upper stage. I quote from this paper (emphasis mine):

  Additional spectral observations were completed in May 2003 at the Air Force Maui Optical Supercomputing (AMOS) site. Through the modeling of common spacecraft materials, the observations of J002E3 show a strong correlation of absorption features to a combination of human-made materials including white paint, black paint, and aluminum. Absorption features in the near IR show a strong correlation with paint containing a titanium-oxide semiconductor.

So, in short: could we do the same with this automobile and find that this is not a plain old space rock? How close would it have to be for this?


texts: Why is VX Sagittarii classified as spectral type M4-M10?

texts: The largest and most luminous asymptotic-giant branch (AGB) star is VX Sagittarii. Wikipedia states that its spectral type is M4eIa-M10eIa (citing https://arxiv.org/pdf/astro-ph/0608438.pdf which in turn cites the General Catalog of Variable Stars).  Additionally, VX Sagittarii's temperature ranges from 2400-3300 K, and 2400 K is well within the range of an M8/M9 class star. Why is its spectral type cited as M10, instead of something more common, like M9.5 or L0 instead?


texts: How many meteors hit the moon every day or in how many days does a new meteor hit the moon?

texts: What is the frequency of meteor strikes on the moon per day?